A serendipitous five-step cascade of rhodium vinylcarbenoids with aminochalcones enables a unique synthetic approach to highly functionalized tri- and tetra-cyclic quinolines. The cascade reaction begins with the insertion of aminochalcone nitrogen into rhodium vinylcarbenoids followed by intramolecular aldol cyclization to provide a substituted indoline intermediate that undergoes an oxy-Cope rearrangement to provide a 9-membered azacycle, which then rearranges to the functionalized quinoline through an intramolecular aldol/dehydration sequence. With a catalyst loading as low as 0.1 mol%, the cascade reaction has proven to be general with a range of aminochalcones and vinylcarbenoids.

A novel diazo-cascade approach has been developed for the synthesis of nine-membered oxacycles utilizing readily accessible β-hydroxy vinyl ketones and vinyl diazo esters. The Rh(II)-catalyzed cascade reaction begins with carbene O–H insertion followed by an intramolecular aldol cyclization to provide a substituted tetrahydrofuran intermediate that undergoes an oxy-Cope rearrangement to provide functionalized nine-membered oxacycles with complete stereoselectivity.